Insert valve and method of insertion into pressurized pipelines

ABSTRACT

A method of cutting and removing a section of prestressed concrete cylinder pipe and then installing a replacement valve while the pipeline is fully pressurized uses a replacement valve body ( 22 ) with two cylinders ( 223 ,  225 ) that match the openings of the cut pipe ( 35 ). Inside each of the two cylinders ( 223 ,  225 ) is a cut-covering assembly ( 62 ) which includes a cylindrical elastomeric seal ( 26 ) and spring tube ( 25 ), and a cross brace ( 27 ) extends between two surfaces within the spring tube ( 25 ). The replacement valve body ( 22 ) further includes a rotatable valve ( 24 ) in a central portion of the valve, and when the cylinder ends of the replacement valve body ( 22 ) are positioned adjacent the bores of cut pipe ends ( 36 ), the valve ( 24 ) can be rotated to push the elastomeric seals ( 26 ) of each of the cut-covering assemblies ( 62 ) into the bores of the cut pipe ends ( 36 ), thereby covering gaps ( 77 ) created when the pipe ( 35 ) was cut and placing the pipe ends ( 36 ) in fluid-tight engagement with the replacement valve body ( 22 ).

BACKGROUND

In the past pipe ends were joined by complex bells and spigots, muchlarger than the pipe’s diameter to allow joining, and theseconfigurations would have to slide together mechanically within apressurized enclosure. On prestressed concrete cylinder pipe (PCCP)where only short work areas can be allowed so the thin cylinder can stayrestrained. With known external pipeline sealing methods, long areas ofthe cylinder would have to be stripped of wire, running the risk of ablowout or a cylinder rupture.

SUMMARY

The present method solves these issues by requiring the temporaryenclosure to be installed in only short areas, and once the enclosure isremoved outside couplings can be installed in the same location as wherethe enclosure seals were placed.

The present method uses the natural movement of a butterfly isolator topush or move internal seals from a replacement valve into the bores ofexisting pipe ends. The action of moving the butterfly's isolator movestwo temporary seals into position to cover entire gaps created bycutting a pipe to insert a valve. These seals temporarily cover cutsmade in the pipe in fluid-tight arrangement between the new valve endsand the existing pipe ends until permanent external seals can beinstalled. This process can be used on most known pipe types.

The size, weight and many difficulties that make valve insertions intopipes complex are reduced by this method that sets a temporary sealinside the pipe sections to allow much smaller permanent fittings to beinstalled after the enclosure is removed in an open, unpressurizedenvironment. There may be applications where bells and spigots wouldhave to be used and other connections could be imagined. The use ofthese alternative connections would not take away from the spirit of howthe restraining method for PCCP pipe is performed.

In addition, I have included a method of restraining pre-stressedtension wire of known PCCP pipe, and a new way to cut and remove thepipe section and then install a new valve and join the new valve withthe exposed pipe ends while the pipeline is fully pressurized.

PCCP pipe is manufactured using a thin steel cylinder to provide afluid-tight membrane and employs a wire wound at high tension aroundthis cylinder that in combination contains the internal pressures usedin pipeline systems.

This method provides the installation of new valves into most types ofpipelines as well as PCCP pipe. Steel, PVC, ductile iron, copper,stainless, transite A/C and cast iron pipe can all utilize this methodto insert a new valve but these other types of pipes are manufacturedfrom a single material so these will not require the restraining methodsas described in detail to allow the safe stripping of concrete or wirein order to expose a work area of the smooth pipe cylinder. For PCCP thecenter clamp is used on all pipe types to retain the center section forcutting and to enable lifting out the cut section into the bonnet asshown, but permanent restrainers will not need to be left in place onpipe that is not PCCP. The process for PCCP pipe and single wall pipetypes can be performed in the same way other than with respect torestraining the concrete and wire on PCCP pipe to expose work areas ofthe smooth cylinder. A smooth cylinder surface exists on other pipetypes without the restraining process.

PCCP pipe has been installed for many years and as the old controlvalves wear out, new isolation valves are needed, and if a change orrepair is required on a system new valves are required to be isolated.The thin steel cylinder used in PCCP cannot contain the workingpressures of the pipeline without the supporting tension wire remainingin place. A process and system for removing the wire to insert a valvehas not been revealed until now.

The tension wire is covered and embedded in the concrete coating to holdthe wire in place and protect the wire from damage and corrosion. Wireis wound at high tension around the steel cylinder to increase thepressure rating. On PCCP pipe if the tension wire is cut or damaged itwill unwind from the cylinder, causing the pipe to lose its strength.The present invention allows the wire to be restrained and cut withoutconcern that the wire will unwind from the cylinder. This system alsoprovides the capability for at least one of the restraints to be removedwith a pipe section and that center restraint replaced with a valvewhile the pipeline is fully pressurized without risk of the wireunwinding from the steel cylinder.

PCCP pipe is composed of a round carbon steel cylinder with wire woundaround it and provides concrete lining and concrete coating. Thisconfiguration of different materials makes installing known types ofinsertion systems not possible for PCCP pipe. Bolting an insert body tothe PCCP concrete coating would not result in a fluid-tight seal, and ifyou removed the concrete to expose the wires there would not be a smoothsurface to permanently seal as the surface is uneven due to the wirebeing wrapped around this cylinder. In addition, removing the tensionwire from the PCCP cylinder in a long area for a valve body to beinstalled is not possible without risking the integrity of the pipe.

The present method was developed to restrain PCCP tension wire alongvarious locations of the pipe and expose short smooth work areas of thePCCP pipe cylinder where permanent and temporary fittings can beinstalled and removed. The method involves restraining a section of pipeby use of a center restraining clamp to support the area, removing asection of pipe, and making an area for to insert a valve with pipe endsinserted and seals that can be simply inserted internally so the lesswire can be removed from the host pipes structure.

On PCCP pipe this process provides for at least two outside restrainingclamps that are mechanically installed onto the pipe coating topermanently retain the coating’s internal tension wires. In addition, atleast one temporary center restraining clamp that surrounds the concretecoating is used to retain the wire, and once the pipe is cut this centerclamp(s) becomes sacrificial and removed with the cut section of pipe.This installation of clamps provides at least two locations where asmooth steel cylinder can be safely exposed to mount a temporaryenclosure. Being able to remove the center clamp under pressure with thesevered pipe provides a method that supports the pipe when needed, andis removed with the clamp under pressure making room for a new valveonce the restraint of the pipe is no longer needed.

By providing at least three restraining clamps that encircle theconcrete coating as shown in this method, the tension wire is held inplace so valve Inserting can be performed on fully a pressurized PCCPpipeline.

This process provides various restraining mechanism(s) or “clamp(s)” tohold wires in place by securing the concrete that holds the embeddedwire. The term “clamp” will be understood to refer to one clamp or tomultiple clamps used in combination that are meant to encircle apipeline’s concrete coating holding it in tension, to retain the wire inplace. The clamps can be tightened around the concrete coating, enablingthe clamps to tightly hold the concrete and embedded wire in position.

To begin the restraining process, at least three clamps are used toprepare the pipe for inserting a valve. The center restraining clamp isalmost as wide as the intended cut section of pipe and this centerclamp’s main function is to support and retain a section of pipe byholding the wire within the pipe coating until the pipe section is cutand the center-clamp is removed with the pipe section under pressure anddiscarded. In addition to the center clamp there is at least one outsideclamp installed on each side of the center clamp to permanently retainthe concrete and wire that support the pipe from internal pressure.

On PCCP pipe, space is provided between the center clamp and eachoutside clamp to allow the removal of concrete and wire to expose thesmooth steel cylinder on each side of the center clamp. This area ofexposed smooth PCCP cylinder allows the installation of a pressureholding container or “enclosure” that can be installed onto the cylinderin a short area.

The exposed smooth areas need to be kept as short as possible. On someapplications it may be necessary to obtain additional short clearworking areas by using additional clamps to remove more than two areasof concrete and wire to expose more smooth work areas. If required, atleast a second set of outside clamps can be installed a short distanceaway on the outside of the initial outside clamps to retain the concreteand wires.

This second set of clamps would be a short distance away and additionalclamps can be installed outside of the initial outside clamps to gainadditional work areas. This process can provide additional accesslocations of the smooth cylinder so enclosure glands and work locationscan be installed in separate areas along the cylinder.

The enclosure attached to the pipe cylinder has a means of accepting aservice valve to be mounted on top and act as a fluid isolator for abonnet so tooling can be installed and removed to complete the newinsert valve installation while the pipeline remains pressurized.Bonnets for use with the present system and method are known to the art,and are described for example in U.S. Pat. Nos. 6983759, 6776184,7021325, and 7021325. A temporary pressure-tight enclosure is installedonto the host pipe in fluid-tight arrangement and seals on the pipe walland on PCCP seals in the short areas of smooth cylinder provided. Thepressure-tight enclosure is split into at least two halves so each endof the container can be assembled onto the existing pipeline by use ofsplit mechanical draw glands that force a split tapered wedge-stylerubber gasket into a receiving area for the wedged rubber on theenclosure to make the fluid-tight seal. The pressure-tight enclosure isbuilt to encompass the center clamp and the intended pipe that will beremoved. The enclosure provides a support for a service valve thatallows various functions to complete the valve insertion.

In addition, the bonnet of the present system is designed to be largeenough to house a stabilizing member and cutting mechanism and providesenough room to receive the cut section of pipe and center clamp with thecutting mechanism and the stabilizing member all at one time if desired.Initially, the bonnet housing with the stabilizing member and thecutting mechanism is held above the service valve. The stabilizingmember is extended to reach the center clamp and both are securedtogether in rigid fashion by bolting or threading. Once the stabilizingmember is secured with the center clamp, the bonnet housing can belowered with the cutting mechanism using the stabilizing mechanism andsecured to the open service valve in fluid-tight arrangement. Oncesecured to the open service valve the cutting mechanism can be loweredinto position by known advancing mechanisms such as a screw jack and apacking seal to keep fluid from passing from the bonnet. With thestabilizing member attached to the center clamp the intended pipe to becut is held in rigid position. The enclosure has pipe supports that canbe advanced or tightened against the exposed cylinder or center clampthat will help hold the pipe section to be cut in a rigid manner. Thecutting mechanism will begin cutting the crown of the pipe and passthrough the entire pipe section.

The cutting mechanism uses a flexible cutting belt that can includecables, wires or have flexible chains similar to a chain saw. Diamondsor known hard particles are attached to perform cutting or abrasiveseparation of the pipe. The cutting mechanism can cut two pathssimultaneously but on some applications only one cut may be performed ata time. The flexible cutting tool provides at least one drive wheel foreach flexible belt and one or more wheels to keep the flexible belttight and movable. The motor to drive the flexible belts can incorporatea direct drive that uses at least one rod or driveline that can passthrough the bonnet to one or more gearboxes. This rotational movementwill drive the wheels to power the belts so a motor can be providedoutside of the pressurized container.

As the cutting penetrates the pipe wall the enclosure becomes fullypressurized by the pipes contents as the fluid enters the enclosure. Theenclosure provides a housing that contains the fluid pressure, so equalpressure will exist on the outside of the pipe as well as the inside ofthe pipe, this allows the center clamp to become sacrificial as the pipesection requires no more restraint of the tension wire at this centerlocation once equal pressure is achieved.

Once the pipe section is completely separated, the stabilizing member isoperated to retract and remove the cut section of pipe that is attachedto the center restraining clamp. The cutting mechanism can be fullyretracted into the bonnet housing with the stabilizing member so theservice valve can be closed. Closing the service valve allows thedepressurization of the bonnet and removal of the bonnet from theservice valve with all the enclosed items. The cut section of pipeattached to the center restraining clamp is removed from the stabilizingmember and the cutting mechanism is removed from the bonnet housing.

A new valve to be inserted into the pressurized system is positioned andsecurely attached to the stabilizing member and moved into the housingof the bonnet. The insertion valve is set in the closed or semi closedposition prior to inserting into the pipeline. Cut-covering assembliesare installed fully into both pipe ends one on each side of the newvalve. The bonnet is reinstalled onto the service valve in fluid-tightarrangement and the bonnet becomes pressurized by opening the servicevalve to allow fluid to pass into the bonnet. Once the service valve isfully opened the stabilizing member securing the new valve with pipeends holding cut-covering assemblies is extended into the fullyinstalled and secure position within the gap left by the removed pipesection.

The cut-covering seals are wider than the gap made in the pipe by thecutting tool. The cut-covering seal may incorporate designs that helpseal the gap created by the pipe being cut. The seal design couldinclude angles, pockets, or any number of imaginable different designsto make up a seal that holds the seal in its desired position, and thatcovers and plugs the cut or gap in a fluid-tight and structurally soundarrangement.

A spring producing cylinder creates outward pressure on the seal to keepthe seal riding on the inside diameter of the pipe walls, keeps thefluid pressure from extruding the seal through the cut and holds the newvalve in position once the service enclosure is removed. Many types ofsupports can be used, but preferably steel or stainless steel rolledunder tension is used to create a round shape that matches the diameterneeded and provides an outward pushing force. The round shape canprovide an overlap that gives the desired expansion needed to add springto the cylinder.

Together this cut-covering assembly provides a spring-loaded sealingmember that supports the valve installation once moved into positionwith the existing pipe ends. The cut-covering assembly is hollow inshape and looks similar to a piston-inserting tool that is used tocompress piston rings prior to sliding the piston into an engine bore.

The cut-covering assembly initially is installed into both pipe ends ofthe new valve. When moved partially into the existing pipe ends thecut-covering assembly will cover the entire cut made around the internaldiameter of the pipe. The cut-covering assembly will end up preferablyhalf in the new valve ends and half in the existing pipe to cover thegap in order to make a fluid-tight seal.

A cross brace is provided on one side of the cut-covering assemblyclosest to the butterfly valve so the butterfly’s isolator can contactthe cut-covering assembly when the butterfly valve operator is rotatedin the open direction. Operating the butterfly valve is performed byproviding a round rod through the bonnet attached to the service valveon the enclosure. A packing seal is provided on the bonnet around theoperational rod to keep fluid from passing out of the bonnet. Byrotating the new valve’s operator in the opening direction the isolatorpushes the cut-covering assembly and slides into the existing pipe to apredetermined location within the existing pipe ends.

With the new valve ends inline with the existing pipe ends, thebutterfly valve is opened to allow the isolator to engage the crossbrace. Upon continuing opening, the isolator slides across the crossbraces as it pushes the cut-covering assembly from its position withinthe new valve ends, preferably halfway into the existing pipe. Thisaction allows the cut-covering assembly to slide through the bore ofboth pipe ends into the existing pipe to a planned location. Bothcut-covering assemblies are pushed and slide in the same manner inopposite directions from the new valve end locations, the cut-coveringassemblies enter into the existing pipes cut ends and continue travelinguntil the valves isolator reaches its fully open position. A portion ofthe cut-covering assembly stays within the new valve’s pipe ends and aportion moves into the existing pipe where the cut or gap is covered influid-tight arrangement. The outward springing action of the tubeprovides even continual outward pressure of the sealing portion of thecut-covering assembly to keep it pressed against the inside diameter ofthe new valve ends and the existing pipe wall, thus securing it inposition while traveling to installing a seal into position over the gapcaused by the cut.

Once the new valve is in position with the existing pipe and theinternal cut-covering assembly is in place the enclosure housing used inthe insertion process can be depressurized. Once depressurization isperformed it will cause the internal pressure of the existing pipelineto press the cut-covering seals tight against the inner walls, securingthe seals into position. The rigid spring tube will keep the seal fromextruding through the cut gap and restrain the new valve in position.

To finish the valve installation process the temporary pressurizedenclosure is removed. Conventional pipe-joining couplings can be placedaround the exterior of the pipe to securely cover both cuts as apermanent completion to the valve installation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of existing pipeline with threerestraining clamps attached, a first outside-restraining clamp, a centerrestraining clamp with a mounting plate and a second outside-restrainingclamp. Once the clamps are installed around the pipeline’s concreteexterior, the clamps retain the concrete coating that holds thetensioned wires in place. Only PCCP pipe requires restraining of tensionwires to provide a smooth clear cylinder.

FIG. 2 is a side elevation view that shows existing a PCCP pipeline withthree restraining clamps in place. These clamps secure the tension wiresby encircling the concrete coating under compression. The concretecoating is removed between the center restraining clamp and outsiderestraining clamps, exposing the tension wires.

FIG. 3 is a side elevation view of a PCCP pipeline with threerestraining clamps installed. The tension wires between the clamps aresafely removed, exposing the smooth steel cylinder to provide safe areaswhere work can be performed. The tension wires are removed between thecenter restraining clamp and the outside restraining clamps, exposingsmooth steel cylinder in two locations where work can be performed.

FIG. 4 is a sectional side elevation view of a PCCP pipeline with threerestraining clamps installed around the concrete coating to secure thetension wires, allowing areas of the steel cylinder to be exposed. Thecenter clamp has a mounting attachment for the stabilizing member toconnect. A pressure holding enclosure is mechanically installed on theexisting pipeline. Using an enclosure with more than one part allowsinstallation of this enclosure in fluid-tight arrangement onto apressurized pipeline. The enclosure provides the means of attaching aservice valve on top. This service valve allows various operations thatare required to perform the insertion valve process.

FIG. 5 is a side elevation view that shows the cutting mechanism thatuses at least one drive wheel and one support wheel to move a flexiblebelt. The belt incorporates attached diamonds, carbides or otherabrasive media to wear through pipelines such as PCCP that are concrete,or the belt can include cutting edges that are sharp to perform cuttingfor pipes such as plastic and iron. In one embodiment the belt caninclude edges similar to a chain saw. In a preferred method themechanism has at least two cutting belts with at least two drive wheelsto sever the pipe section with one movement. Some pipelines may requireone cut to be performed at a time. This figure shows a gearbox that isdriven by a shaft which extends outside of the bonnet so that a powerunit can be used to turn the belts.

FIG. 6 is a perspective view depicting a gear box that turns drivewheels that power the movement of the belt to cut the pipe. The belt isimpregnated with diamonds or other cutting medium. A number of existingproducts using flexible cables and wire that cuts material can be used.This illustration shows how the cutting assembly can be arranged andused to turn two flexible belts. The belts are used to makeperpendicular cuts through the pipe section so a section of pipe can becut and removed from a pipeline after a section of pipe is severed.

FIG. 7 is a sectional side elevation view that shows a bonnet attachedto a service valve. The service valve is in the fully open position,allowing the stabilizing member to advance and retract when the servicevalve is in the open position. The bonnet shown is retaining the centerclamp in position. There are brackets as part of the enclosure thatsupport the proposed section of pipe to be cut, keeping it rigid betweenthese brackets and the stabilizing member. The cutting mechanism isshown to be advancing toward the pipeline and retracted by means of afeed screw that can be operated by rotating two screw jacks, though asingle jackscrew can be used. The cutting tool uses power drive headsthat is shown to rotate two belts that have diamonds, cutting orabrasive medium attached. Two belts are shown to perform twosimultaneous cuts at the same time to separate a pipe section. Onvarious projects it may be required to make a single cut at a time buttwo are shown for simplicity. The cutting mechanism feed screw can alsobe used to operate the new valves isolator to the open or closedposition.

FIG. 8 is a sectional side elevation view of the configuration of FIG. 7but showing the cutting tool having passed completely through the pipe,severing the intended pipe section and revealing the gap left by thecut. This creates two pipe ends of the existing pipe. The illustrationalso shows the enclosures brackets that have retained the cut section ofpipe during the cutting process and the same brackets will position thenew valve into a precise position when installed.

FIG. 9 is a sectional side elevation view of the configuration of FIG. 7that shows the bonnet and service valve of FIGS. 7 and 8 after severingthe pipe. The center restraining clamp and pipe section are both removedtogether into the housing by retraction of the stabilizing member. Thisprocess provides an area where the new valve will be installed. Inaddition to the removal of the cut pipe and clamp, the cutting tool isremoved from the enclosure into the bonnet and the service valve isclosed. The bonnet as shown has been depressurized and removed from theenclosure.

FIG. 10 is a sectional side elevation view of the configuration of FIG.7 that shows the new valve with its attached pipe ends, each holding acut-covering assembly and attached to the stabilizing member. The newvalve is retracted into the housing of the bonnet by retraction of thestabilizing member. The bonnet is reattached onto the service valve soit can be fully opened to allow passing of the new valve into theposition or existing gap left behind by the removal of the cut sectionof pipe.

FIG. 11 is a sectional side elevation view of the configuration of FIG.7 that shows the stabilizing member advanced and placing the new valveinto a rigid position with the enclosure centering brackets. This rigidinstallation of the valve provides the valve’s pipe ends to be inlinewith the existing pipes cut ends. The new valve is stabilized into aposition to allow precise alignment of the new and existing pipe bores.This illustration shows the gap 77 between the existing pipe ends andthe new valves pipe ends.

FIG. 12 is a side elevation view that shows the new valve ends installedin direct alignment with the existing pipe ends. The cut-coveringassemblies provide spring-loaded sealing members (25, 26) housed withinthe new valve ends, which are wide enough to remain in a portion of thenew valve ends, cover the cut gap in the pipe, and enter into theexisting pipe ends.

FIG. 13 is a sectional view of the cut-covering assembly. The outsidecircle is a pipe wall, the hashed-marked area is the rubber or flexiblecompound seal, and the overlapping internal line is the spring-typecylinder that is rolled to provide exterior expansion and can be pulledtogether prior to being inserted into the new valve ends so it willnaturally want to expand, creating a force on the sealing member to keepit along the pipe’s interior in the new valve’s pipe ends or the insidediameter of the existing pipeline.

FIG. 14 is a sectional view showing an embodiment of the sealing portionof the cut-covering assembly and how the rubber could be held intoposition in relationship with the spring tube. The cut-covering assemblyseal is covering the gap cut in the pipe, a portion of the existing pipeinterior and a portion of new valve pipe interior. The gap is shownabove the seal design and is covered continually around the wholediameter of the pipe to create a fluid-tight seal of the gap.

FIG. 15 is a side sectional view that depicts the new valve ends beinginstalled in direct alignment with the existing pipe ends. The new valvecan be opened under pressure by using a rod that passes through thebonnet and is connected to the operating nut of the butterfly valve. Aseal is provided on the bonnet to keep fluid from escaping. By turningthe operating mechanism in the direction that opens the new valve, bothcut-covering assemblies (one on each side of the new valve) are evenlypushed by direct engagement of the butterfly isolator. The naturalmovement when opened keeps the cut-covering assemblies evenly moved to apredetermined location. The isolator of a butterfly valve when openeduses a pivoting movement to rotate a disc, and as the disc rotates itincreases in length into the new valves pipe ends making it contact thecut-covering assemblies. A cross brace structure is provided on thecut-covering structure so the whole assembly can be moved by theisolator engagement and the isolator can freely slide from one end ofthe cross brace to the center as the rotating movement progresses. Thisengagement moves both sides of the cut-covering assemblies away from thenew valve at the same time and rate into the shown position where theseal can reside in the new valve’s pipes, cover the gap, and reside inthe existing pipe. This procedure allows both seals to be gently placedinto position, ready for depressurization of the enclosure that willseal both cut-covering assemblies to the pipe’s interior.

FIG. 16 is a side elevation view that presents the completely insertedvalve with permanent fittings attached over the cut gap. The typicalfitting is known in the industry as a standard “coupling”. The couplingcovers and permanently seals the gap that is temporarily internallyplugged by the cut-covering assembly, thereby completing the method ofinserting a valve into a live pipeline. These couplings can be installedloose on the new valve’s pipe ends during insertion so split stylecouplings will not have to be used.

FIG. 17 is a side elevation view that shows how multiple clamps can beused to expose more than two work areas of clear smooth pipe cylinderfor work that may be required on PCCP pipe.

FIG. 18 is a perspective view of the spring tube and cross braces of anembodiment of a cut-covering assembly.

FIG. 19 is a perspective view of the spring tube and cross braces ofanother embodiment of a cut-covering assembly.

FIG. 20 is a front elevation view of the spring tube and cross braces ofthe embodiment of a cut-covering assembly of FIG. 19 .

FIG. 21 is a side sectional view of the spring tube and cross braces ofthe embodiment of a cut-covering assembly of FIG. 19 along line A-A ofFIG. 20 .

FIG. 22 is a perspective view of an embodiment of a replacement valveassembly.

FIG. 23 is a front elevation view of the replacement valve assembly ofFIG. 22 .

FIG. 24 is a side sectional view of the of the replacement valveassembly of FIG. 22 along line A-A of FIG. 23 .

FIG. 25 is a perspective view of the replacement valve assembly of FIG.22 attached to a service valve and bonnet.

FIG. 26 is a front elevation view of the replacement valve assembly,service valve and bonnet of FIG. 25 .

FIG. 27 is a side sectional view of the replacement valve assembly,service valve and bonnet of FIG. 25 along line A-A of FIG. 26 .

The reference numbers in the figures refer to the following:

Component Reference Number tension wire 1 outside restraining clamp 2left side restraining clamp 211 right side restraining clamp 212 secondleft side restraining clamp 2A second right side 2B restraining clampcenter restraining clamp 3 bolts (with nuts) 4 concrete coating 5mounting flange 6 cylinder 7 pressurized enclosure / housing 9 servicevalve 10 mechanical gland 11 wheels 12 abrasive belts 13 stabilizingmember 15 jack screws 17 internal bracket of the housing 19 pipe section20 new pipe end assemblies 21 new valve body 22 valve body right side221 valve body left side 222 valve body right side cylinder 223 rightside cylinder interior 2231 right side cylinder opening 224 valve bodyleft side cylinder 225 left side cylinder interior 2251 left sidecylinder opening 226 central chamber 227 fluid passage 228 operating nut23 disc (isolator) / valve 24 first medial edge 241 second medial edge242 seal 26 seal exterior 261 seal interior 262 internal spring tube 25spring tube exterior 251 spring tube interior 252 cross brace 27 firstcross brace 271 second cross brace 272 cross brace medial flange 275cutting tool 30 bonnet 32 pipe (pipeline) 35 left side of the pipe 351right side of the pipe 352 left medial portion of the pipe 353 rightmedial portion of the pipe 354 pipe ends 36 replacement valve assembly40 gearbox 50 shaft 51 drive unit 52 cut-covering assembly 62 right sidecut-covering assembly 621 left side cut-covering assembly 622 rod 72 cutgap 77 receiving cavity 87 wedged rubber 88

DETAILED DESCRIPTION

As seen in FIGS. 1-3 , tension wires 1 are embedded within the concretecoating 5 of a pipeline made with PCCP pipe. Restraining clamps 2 remainpermanently a part of the pipeline 35 to the keep the wire 1 in tensionaround cylinder 7 to secure the strength of pipeline 35. Centerrestraining clamp 3 is temporary and is installed a short distance awayfrom outside clamps 2 to provide smooth areas of cylinder 7 free of wire1 and concrete 5 without risking the loss of pipe 35 strength. Clampscan be formed from a combination of pieces joined for example by bolts4, as shown in the illustrated embodiments. Restraining clamps 2 and 3are designed to hold the various sizes of pipelines 35 and accommodateinternal working pressures. A mortar mix can be applied to make up forout-of-round surfaces of concrete 5.

The center restraining clamp 3 can be made up of a combination of piecesto make one clamp or a combination of clamps with multiple pieces asseen in FIG. 1 to make up the center restraining clamp 3. The centerclamp 3 is provided with a mounting flange 6 that mates with stabilizingmember 15. The stabilizing member 15 preferably attaches to mountingflange 6 by common threading or bolting. Threading is preferred becauseit is a stabilizing member that allows attachment and detachment(screwing and unscrewing) under pressure. The center restraining clamp 3is installed around pipeline 35 encircling its concrete coating 5 tosecure the tension wires 1 that support cylinder 7.

Clamps 2, 3 are preferably assembled by bolting 4, and the outsideclamps 2 are installed a predetermined distance and outside ofcenter-clamp 3. The outside-restraining clamps 2 can consist of a singleclamp or a combination of clamps to make up the outside-restrainingclamp 2. Bolts and nuts 4 are used to assemble restraining clamps 2, 3.These outside restraining clamps 2 can remain as a permanent part of thepipeline 35.

Multiple outside restraining clamps can be used and left in place toprovide additional service locations along the steel cylinder 7 fortooling or services. For example, as seen in FIG. 17 a second left siderestraining clamp 2A placed to the left of the left side restrainingclamp 211 and a second right side restraining clamp 2B placed to theright of the right side restraining clamp 212 can be attached to thepipe 35.

The center restraining clamp 3 seen in FIGS. 1-4 has a smaller width,like that of the new valve 22 with its sub-assemblies 21. The centerrestraining clamp 3 is removed from its position with pipe section 20 asseen in FIG. 9 . When the section 20 is cut by the cutting tool 30 (seeFIGS. 5, 7 ) this removing section 20 includes removal of the centerrestraining clamp 3 as shown in FIG. 9 while the pipeline 35 is fullypressurized. Enclosure 9 allows equal pressure inside and outside ofpipeline 35 so this removal of cut section 20 can be performed. Theremoval of the center restraining clamp 3 with cut section 20 could nottake place without an equal pressure condition of pipeline 35. Once thewire 1 is cut to expose the smooth cylinder 7 and clamp 3 is removed,the wire 1 would separate from cylinder 7 and the unsupported cylinder 7would run the risk of rupturing after wire 1 is removed.

Using the present method, by encapsulating the center restraining clamp3 with enclosure 9 to provide exterior pressurization of pipeline 35with the same pressure as the inside of pipeline 35, no stress existsfrom internal pressure on cylinder 7. This allows cutting and removingcenter restraining clamp 3 with the pipe section 20 from pipeline 35 tobe safely performed. In addition, equal pressure produced by enclosure 9allows the cut-covering assemblies 62 to be inserted smoothly with verylittle resistance and without fluid pressure escaping through gap 77.Unequal pressure would affect the movement of the cut-coveringassemblies 62 into the pipe ends 36.

The pressurized enclosure 9 shown in FIG. 4 connects onto the pipeline35 using mechanical seal or gland 11 that by bolting pushes andcompresses a wedged rubber (elastomeric) gasket 88 into a receivingcavity 87 on enclosure 9. The gasket 88 surrounds the pipe and ispreferably cut at a tapered angle to form a wedge and wrapped around thepipe in cavity 87 so that when the ring member 11 is tightened it sealsthe cut rubber edges by compression all the way around the pipe to forma mechanical joint. This multi-piece enclosure 9 is installed on a cleararea of a cylinder 7 or on a smooth pipe 35.

Enclosure 9 has a mounting surface 28 where a service valve 10 connectsso that a bonnet 32 can be installed and removed to perform variousservices. Attached to bonnet 32 is a stabilizing member 15 that can beretracted and advanced to restrain clamp 3 by mounting flange 6. Clamp 3is attached to pipe section 20 to retain the pipe section in positionfor cutting.

Abrasive belts 13 which rotate on the cutting tool 30 can be used, asshown in FIG. 5 and FIG. 6 . At least one gearbox 50 can be providedthat can be powered by a shaft 51 that passes through the housing 9 orbonnet 32 to connect to a drive unit 52 so the belts 13 can move to cutthe pipeline 35. Using an external drive 52 can allow a hydraulic orelectric drive 52 without being under water or pressurized within thehousing 9.

The provided wheels 12 keep the belt 13 tight and drive the belt toperform cutting of a section of pipe 20 from pipeline 35. Advancing thejack screws 17 on FIG. 7 moves the cutter 30 to advance the cut andretract afterward, i.e., to move the cutter 30 up and down in thehousing 9 or bonnet 32. Cut section 20 being attached to clamp 3 allowsboth to be retracted along with cutting tool 30 by member 15 into thehousing 32. Once retracted, the service valve 10 can be closed toisolate pressure found in existing pipeline 35.

As seen in FIG. 9 , the housing 32 can be removed from service valve 10.The cutting tool 30 along with the removed pipe section 20 and thecenter clamp 3 are removed from the housing. As seen in FIG. 10 , a newvalve 22 with pipe ends 21 can then be attached. Cut-covering assemblies62 are placed within each pipe end 21 and the valve 22 is secured tostabilizing member 15 and retracted into housing 32 so the housing 32can be bolted to service valve 10. Once housing 32 is secured to servicevalve 10 it can be fully opened to pressurize housing 32 allowing thenew valve with end assemblies 21 to be installed where pipe section 20was removed from the existing pipeline 35, creating existing pipe ends36 as seen in FIG. 10 .

As seen in FIG. 11 , new valve 22 with attached pipe ends 21 containingcut-covering assemblies 62 are set into alignment by stabilizing member15 and internal bracket 19 of the enclosure 9. The lower brackets 19found in the housing 9 are designed to cradle the new valve 22 in trueplacement and the stabilizing member 15 is set tight to hold valve 22 inplace and enable the bores of attached pipe ends 21 and the existingpipe ends 36 to match. The inside diameters of pipes 21 and existingpipe 36 are placed in alignment and in the same plane with one another.This allows the cut-covering assembly 62 to easily slide through allbores of the pipe ends without restriction.

Set within each new valve pipe ends 21 is the cut-covering assembly 62as seen in FIGS. 12-15 . This cut-covering assembly is set within bothpipe ends 21 and arranged to clear existing pipe ends 36 while being setinto the gap created by removal of cut section 20 as seen in FIG. 12 .

After the new valve assembly 22 and sub assemblies 21 are in position,the new valve 22 can be operated within the pressurized enclosure 9 byrotating control rod 72 as seen in FIG. 15 .

Operating this control rod 72 turns operating nut 23 of the valve 22 torotate a disc 24 or “isolator”. As seen in FIG. 15 , the isolator disc24 being opened in pivoting fashion moves the disc 24 out of the valvebody 22. This continued pivoting of disc 24 causes direct contact withcross brace 27 of the cut-covering assembly 62, and forces cut-coveringassemblies 62 to be pushed away on each side from valve 22 and itssecured placement within pipe 21 into pipe ends 36. Cut-coveringassembly 62 continues to move into existing pipe ends 36 by directcontact with the isolator 24 until they slide to their predeterminedposition. At that point the new valve 22 and isolator 24 are in thefully open position. The cut-covering assembly 62 will stay in positiondue to tension created on seal 26 by the internal spring tube 25installed as part of the cut-covering assembly 62 and will not obstructthe closing of the valve.

Cut-covering assembly 62 is installed partially into the existingpipeline 36 to a point which is at least enough to cover cut gap 77 (asseen in FIGS. 8, 12, 14, and 15 ) in fluid-tight engagement. Thecut-covering assembly 62 as seen in FIGS. 12, 13, and 14 includes aspring tube inner structure 25 to keep the seal 26 tight against thepipe walls of 21 and 35 inside the pipe diameters. Once cut-coveringassembly 62 has traveled into position to cover gap 77, the pressurewithin the enclosure 9 can be released, causing the seal of cut-coveringassembly 62 to seat tightly with the inner walls of pipe 35 and pipeassemblies 21.

Once the temporary enclosure 9 is depressurized, it can be removed fromthe pipeline 35 and permanent external closure couplings 40 (seen inFIG. 16 ) are installed to cover gap 77 to complete the valve insertion.

One embodiment of a replacement valve assembly 40 for use in the presentmethod can be seen in FIGS. 22-24 . The replacement valve assembly 40includes a valve body 22 having a right side 221 and a left side 222.The right side 221 of the valve body 22 has a right side cylinder 223for engaging a right side end of the cut pipe 35, while the left side222 has a left side cylinder 225 for engaging a left side end of the cutpipe 35. In between the right side cylinder and left side cylinder ofthe replacement valve assembly 40 is a central chamber 227. The centralchamber 227, right side cylinder 223, and left side cylinder 225 aredisposed along a longitudinal axis and are in fluid communication so asto form a fluid passage 228 between a right side cylindrical opening 224of the right side cylinder 223 and a left side cylindrical opening 226of the left side cylinder 225. The central chamber 227 further includesa rotatable valve 24, which can be a butterfly valve, and can be in theshape of a disc.

Each of the cylinders of the replacement valve assembly 40 includes acut-covering assembly 62, components of which can be seen in FIGS. 18-21. A right side cut-covering assembly 621 is positioned in an interior2231 of the right side cylinder 223 and a left side cut-coveringassembly 622 is positioned in an interior 2251 of the left side cylinder225. Each cut-covering assembly includes an elastomeric seal 26, aspring tube 25, and a first cross brace 27. The exterior surface 261 ofthe elastomeric seal 26 contacts an interior surface of the cylinder ofthe replacement valve assembly 40, and an exterior surface 251 of thespring tube 25 contacts an interior surface 262 of the elastomeric seal26. The spring tube exerts pressure (force) outwardly, i.e. on theinterior surface 262 of the elastomeric seal 26, and assists in creatinga fluid tight seal with the seal 26. One or more cross braces 27 extendwithin the fluid passage 228 of the valve body 40 in the central portionof the cut-covering assembly 621, extending between a first position2521 on the interior surface of the spring tube and a second position2522 on the interior surface of the spring tube 25. The cross braces 27engage the spring tube 25 and/or the seal 26 so that when a longitudinalforce is exerted on the cross brace 27 the cut-covering assembly 62 canbe moved outwardly.

In some embodiments, a cut-covering assembly 62 can include both a firstcross brace 271 and a second cross brace 272. The cross braces 27 canoptionally include a medial flange 275 that extends inwardly toward thecentral chamber 227 in order to make better contact with the rotatablevalve 24. In the illustrated embodiments, the medial flange is a bentrod attached at both ends to the cross brace 27.

When the rotatable valve 24 is rotated between a first position and asecond position, a first medial edge 241 of the valve contacts the crossbrace(s) of the right side cylinder 223 and urges a right side end ofthe right side cut-covering assembly 621 out of the right sidecylindrical opening 224, i.e. so that the seal 26 and spring tube 25 canbe moved into the open end of cut pipe adjacent to the right side of thereplacement valve assembly 40. Simultaneously, a second medial edge 242of the valve 24 (opposite the first medial edge) contacts the crossbrace of the left side cylinder 225 and urges a left side end of theleft side cut-covering assembly 622 out of the left side cylindricalopening 226 and into the open end of cut pipe adjacent to the right sideof the replacement valve assembly 40. In this way, the two open ends ofthe replacement valve assembly 40 can be placed into fluid communicationand fluid-tight engagement with the cut ends of the pipe 35.

An assembly including the replacement valve assembly 40 of FIGS. 22-24 ,a service valve 10, and a bonnet 32 for use as described above are shownin FIGS. 25-27 .

The examples set forth herein are provided to illustrate certainconcepts of the disclosure. The apparatus, devices, or componentsillustrated above may be configured to perform one or more of themethods, features, or steps described herein. Those of ordinary skill inthe art will comprehend that these are merely illustrative in nature,and other examples may fall within the scope of the disclosure and theappended claims. Based on the teachings herein those skilled in the artshould appreciate that an aspect disclosed herein may be implementedindependently of any other aspects and that two or more of these aspectsmay be combined in various ways. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, such an apparatus may be implemented orsuch a method may be practiced using other structure, functionality, orstructure and functionality in addition to or other than one or more ofthe aspects set forth herein.

DEFINITIONS

As used herein, the following terms and variations thereof have themeanings given below, unless a different meaning is clearly intended bythe context in which such term is used.

“Brace” refers to a structural component attached to a structure inorder to strengthen and/or support the structure.

“Clamp” refers to a component which exerts pressure on the outer surfaceof a pipe in the present system. Clamps used in the present system andmethod exert sufficient binding force to restrain the tension wires inPCCP pipe with sufficient force to prevent the tension wires from losingtension.

“Prestressed Concrete Cylinder Pipe” (PCCP) refers to a pipe formed froma concrete core, a thin steel cylinder, high tensile prestressing wiresand a mortar coating. The concrete core is the main structuralload-bearing component, with the steel cylinder acting as a waterbarrier between the concrete layers. The prestressing wires produce auniform compressive pressure in the core that offset tensile stresses inthe pipe, and the mortar coating protects the prestressing wires fromphysical damage and external corrosion.

In addition, the terms “above,” “below,” “between,” and other terms ofrelative position or orientation as used herein refer to a relativeposition of one layer with respect to other layers. As such, one layerdeposited or disposed above or below another layer may be directly incontact with the other layer or may have one or more intervening layers,unless described otherwise herein.

The term “comprise” and variations of the term, such as “comprising” and“comprises,” are not intended to exclude other additives, components,integers or steps. The terms “a,” “an,” and “the” and similar referentsused herein are to be construed to cover both the singular and theplural unless their usage in context indicates otherwise. Ranges whichare described as being “between” two values include the indicatedvalues.

1. A replacement valve assembly 40, comprising: a valve body having aright side and a left side, the valve body comprising a right sidecylinder, a left side cylinder, and a central chamber between the rightside cylinder and the left side cylinder, wherein the central chamber,the right side cylinder, and the left side cylinder are disposed along alongitudinal axis and are in fluid communication so as to form a fluidpassage between a right side cylindrical opening of the right sidecylinder and a left side cylindrical opening of the left side cylinder,and wherein the central chamber comprises a rotatable valve; and a rightside cut-covering assembly in an interior of the right side cylinder anda left side cut-covering assembly in an interior of the left sidecylinder, wherein each cut-covering assembly comprises an elastomericseal, a spring tube, and a first cross brace, wherein an exteriorsurface of the elastomeric seal contacts an interior surface of thecylinder, an interior surface of the elastomeric seal contacts anexterior surface of the spring tube, and the first cross brace extendswithin the fluid passage of the valve body between a first position onthe interior surface of the spring tube and a second position on theinterior surface of the spring tube, wherein when the rotatable valve isrotated between a first position and a second position, a first medialedge of the valve contacts the first cross brace of the right sidecylinder and urges a right side end of the right side cut-coveringassembly out of the right side cylindrical opening, and simultaneously asecond medial edge of the valve contacts the first cross brace of theleft side cylinder and urges a left side end of the left sidecut-covering assembly out of the left side cylindrical opening.
 2. Thereplacement valve assembly of claim 1, further comprising a second crossbrace in each of the cut covering assemblies.
 3. The replacement valveassembly of claim 1, wherein each of the cross braces comprises a medialflange, wherein the medial flange extends inwardly toward the centralchamber.
 4. The replacement valve assembly of claim 3, wherein themedial flange is a bent or curved bar that joins the cross brace at bothends of the bar.
 5. The replacement valve assembly of claim 1, whereinthe rotatable valve is a butterfly valve.
 6. A method for replacing avalve in a pipe, comprising: placing a housing in fluid-tight engagementwith the pipe on a right side and left side of the valve; cutting thepipe on the right side and left side of the valve, thereby creating aright side opening and a left side opening in the pipe; removing thevalve through the housing; advancing a replacement valve assembly intothe housing, wherein a cut-covering assembly is disposed within eachpipe end of the replacement valve assembly, each cut-covering assemblycomprising a cylindrical, elastomeric seal, a spring tube within theseal and a cross brace in the interior of the spring tube, the valveassembly further comprising a rotatable valve between the cut-coveringassemblies; placing the pipe ends of the valve assembly into alignmentwith the right side opening and the left side opening of the pipe; androtating the valve between a first position and a second position,wherein a first medial edge of the valve contacts a cross brace of aright side cut-covering assembly in a right side cylinder of the valveassembly and urges a right side end of the right side cut-coveringassembly out of the right side cylinder, and simultaneously a secondmedial edge of the valve contacts a cross brace of a left sidecut-covering assembly in a left side cylinder of the valve assembly andurges a left side end of the left side cut-covering assembly out of theleft side cylinder, thereby pushing the cut-covering assembliesoutwardly through pipe ends and into the cut ends of the pipe andplacing the valve assembly into fluid-tight engagement with the cut endsof the pipe.
 7. The method of claim 6, wherein the pipe is a prestressedconcrete cylinder pipe (PCCP) having a concrete outer layer, an interiormetal cylinder, and wire 1 wound around the metal cylinder, furthercomprising the steps of: placing a left side restraining clamp onto aleft side of the pipe and a right side restraining clamp onto a rightside of the pipe, thereby restraining pre-stressed tension wire on aright side and a left side of the pipe; placing a center restrainingclamp on the pipe between the left side restraining clamp and the rightside restraining clamp, thereby restraining pre-stressed tension wire ina center portion of the PCCP pipe, wherein the center restraining clampcomprises an upper mounting flange on an upper portion of the clamp;removing the concrete layer and the tension wire in the left medialportion of the pipe and in the right medial portion of the pipe, therebyexposing the interior metal cylinder in the left medial portion and theright medial portion; placing the housing around the center restrainingclamp so that a left side opening of the housing surrounds the interiormetal cylinder in a left medial portion of the pipe to the left of thecenter restraining clamp and a right side opening that surrounds theinterior metal cylinder in a right medial portion of the pipe to theright of the center restraining clamp, wherein the housing is placed influid-tight engagement with the pipe.
 8. The method of claim 6, furthercomprising the steps of attaching a service bonnet to an upper portionof the housing, wherein the upper portion of the housing comprises anupper opening to allow communication between the housing and the servicebonnet, and wherein cutting the pipe comprises advancing a cutting toolfrom the bonnet through the upper opening and cutting the pipe in theleft medial portion and right medial portion of the pipe, therebyseparating a central portion of the pipe containing the centerrestraining clamp.
 9. The method of claim 8, wherein a service valve isincluded between the housing and the service bonnet, and wherein theservice valve is in communication with the upper opening of the housing.10. The method of claim 6, wherein the left side opening of the housingand the right side opening of the housing each comprise an elastomericmaterial.